* {
	margin: 0;
	list-style: none;
	padding: 0;
	box-sizing: border-box;
}
.xy_center {
	left: 50%;
	top: 50%;
	transform: translate(-50%, -50%);
}
#app {
	width: 100vw;
	height: 100vh;
	background-color: #000;
}
ul {
	width: 100%;
	height: 100%;
	position: relative;
	overflow: hidden;
}
li {
	visibility: hidden;
	position: absolute;
	transition: all 4s ease-in;
	left: 50%;
	top: 50%;
	transform: translate(-50%, -50%);
	width: 0;
	height: 0;
}
img {
	max-width: 100%;
	max-height: 100%;
}

.go {
	width: 400px;
	height: 400px;
}

